Enhancement Of Mechanical Properties Research Articles

Green synthesis of multifunctional natural rubber-lignin nanocomposites: A sustainable approach for waste reduction

Lignin, a valuable biomaterial having an array of exciting properties is increasingly favoured as a reinforcement material in the fabrication of green composites. Reinforcement in biopolymers like natural rubber (NR) using lignin nanoparticles (LNP) is considered a hotspot today. In this study, LNP synthesized via the homogenization method was incorporated into natural rubber latex (NRL) using probe sonication, and NR/Lignin nanocomposites (NR/LNP) were fabricated using latex dipping method. The addition of LNP resulted in significant enhancements in mechanical and antibacterial properties, biodegradability, and ultraviolet (UV) blocking capabilities with the addition of 7 parts per hundred rubber (phr) of LNP, due to the uniform dispersion and effective interaction between NR and LNP. This research demonstrates a versatile pathway for integrating LNP into NR through a green method, enabling the production of eco-friendly NR nanocomposites for multifunctional applications. This pathway contributes to a safe disposal of NR based products.

Enhancement in Mechanical Properties of AA5052 Sheet for Small Ship by Cold Roll-Bonding Process

A cold roll-bonding (CRB) process was applied to enhance the mechanical properties of AA5052 sheet for small ship. Two and four AA5052 sheets of 1 mm thickness, 40 mm width and 300 mm length were stacked, then roll-bonded to a thickness of 0.5 mm and 1 mm respectively by two-pass rolling after such surface treatment as degreasing and wire brushing. The rolling was performed at ambient temperature without lubricant using a 4-high mill at rolling speed of 6.0m/sec. The as roll-bonded AA5052 sheet was then annealed for 1h at various temperatures from 200 to 500℃. The as roll-bonded AA5052 sheets showed a deformation structure in which the grains are elongated to the rolling direction, however above 300℃ they exhibited the complete recrystallization structure consisting of equiaxed grains, regardless of the stack number. The grain diameter of specimens annealed at high temperatures above 300℃ was smaller in 4-layer stack than in 2-layer stack CRB. Both tensile strength and elongation of the specimens were better in 4-layer stack than in 2-layer stack CRB. The effects of stacking number on microstructure and mechanical properties of AA5052 sheets processed by CRB and subsequent annealing were discussed in detail.

Influence of Al and Ti Alloying and Annealing on the Microstructure and Compressive Properties of Cr-Fe-Ni Multi-Principal Element Alloy

This study meticulously examines the influence of aluminum (Al) and titanium (Ti) on the genesis of self-generated ordered phases in high-entropy alloys (HEAs), a class of materials that has garnered considerable attention due to their exceptional multifunctionality and versatile compositional palette. By meticulously tuning the concentrations of Al and Ti, this research delves into the modulation of the in situ self-generated ordered phases’ quantity and distribution within the alloy matrix. The annealing heat treatment outcomes revealed that the strategic incorporation of Al and Ti elements facilitates a phase transformation in the Cr-Fe-Ni medium-entropy alloy, transitioning from a BCC (body-centered cubic) phase to a BCC + FCC (face-centered cubic) phase. Concurrently, this manipulation precipitates the emergence of novel phases, including B2, L21, and σ. This orchestrated phase evolution enacts a synergistic enhancement in mechanical properties through second-phase strengthening and solid solution strengthening, culminating in a marked improvement in the compressive properties of the HEA.

Study on enhancing mechanical and thermal properties of carbon fiber reinforced epoxy composite through zinc oxide nanofiller

This study investigates the enhancement of mechanical and thermal properties of carbon fiber reinforced epoxy composites by incorporating zinc oxide (ZnO) nanofillers. The composites were developed by adding 3–15 g of ZnO nanoparticles into the epoxy matrix and were evaluated through experimental testing. The results showed significant improvements in mechanical performance, with the maximum tensile strength of 112.49 MPa and flexural strength of 114.82 MPa at the 15 g ZnO concentration. SEM analysis revealed a reduction in void content and improved fiber-matrix adhesion, enhancing load transfer. Thermal conductivity is 13.47 W/mK, while the coefficient of linear thermal expansion is 9.29 × 10−5/°C, indicating superior thermal stability. TGA analysis demonstrated a shift in decomposition temperature from 310 to 375 °C, confirming enhanced thermal stability. These results highlight the positive influence of ZnO nanofillers on both the mechanical and thermal properties of carbon fiber reinforced epoxy composites, making them more suitable for advanced structural applications.

Ti3C2Tx-UHMWPE Nanocomposites-Towards an Enhanced Wear-Resistance of Biomedical Implants.

There is an urgent need to enhance the mechanical and biotribological performance of polymeric materials utilized in biomedical devices such as load-bearing artificial joints, notably ultrahigh molecular weight polyethylene (UHMWPE). While two-dimensional (2D) materials like graphene, graphene oxide (GO), reduced GO, or hexagonal boron nitride (h-BN) have shown promise as reinforcement phases in polymer matrix composites (PMCs), the potential of MXenes, known for their chemical inertness, mechanical robustness, and wear-resistance, remains largely unexplored in biotribology. This study aims to address this gap by fabricating Ti3C2Tx-UHMWPE nanocomposites using compression molding. Primary objectives include enhancements in mechanical properties, biocompatibility, and biotribological performance, particularly in terms of friction and wear resistance in cobalt chromium alloy pin-on-UHMWPE disk experiments lubricated by artificial synovial fluid. Thereby, no substantial changes in the indentation hardness or the elastic modulus are observed, while the analysis of the resulting wettability and surface tension as well as indirect and direct invitro evaluation do not point towards cytotoxicity. Most importantly, Ti3C2Tx-reinforced PMCs substantially reduce friction and wear by up to 19% and 44%, respectively, which was attributed to the formation of an easy-to-shear transfer film.

Improved interfacial compatibility between unsaturated polyester resin and rice straw fibers after non-washing treatment with Ca(OH)2

The agricultural industry produces a substantial volume of rice straw (RS) annually, highlighting the importance of recycling RS for sustainable materials. However, the poor interfacial compatibility between RS and polymers often leads to drawbacks in their composites, such as water-swelling and limited tensile strength. Here, we propose a novel approach using Ca(OH)2 that offers several distinct advantages: enhancement of interfacial compatibility, elimination of the need for water washing, and formation of calcified hybrid particles on fiber surfaces by capturing CO2 from the atmosphere. The non-washing calcified rice straw (NCRS) fibers were used to fabricate composites with unsaturated polyester resin (UPR), resulting in NCRS/UPR composites exhibiting significant enhancements in water resistance and mechanical properties compared to RS/UPR composites. The NCRS/UPR composites achieved a water absorption rate below 25 %, thickness swelling rate below 10 %, and tensile strength of 19.9 MPa. This work comprehensively explored the mechanism underlying these achievements through experimental studies. Findings suggest that CaCO3 particles involving with released lignin act as an interfacial bridge between RS fiber surface and UPR, resulting in significantly improved properties. This approach demonstrates promising prospects as a simple and eco-friendly methodology for manufacturing RS-based composite materials.

Enhancing mechanical properties of carbonated steel slag through surfactant-assisted CaCO3 crystallization

This study investigates the enhancement of mechanical properties in carbonated steel slag through surfactant-assisted CaCO3 crystallization. Sodium dodecyl benzene sulfonate (SDBS) was employed at various concentrations (0.1–0.4 mol/L) and temperatures (20–60 °C) to modulate the carbonation process. Optimal performance was achieved with 0.2 mol/L SDBS at 40 °C, resulting in a maximum CO2 uptake of 8.51 % and a compressive strength of 62.89 MPa, 81.66 % higher than unmodified steel slag. Characterization techniques confirmed the formation of crystalline calcite, vaterite, and aragonite, contributing to improved microstructure and strength. SDBS micelles act as templates for CaCO3 nucleation and growth, with low concentrations facilitating carbonation and high concentrations inhibiting it. This research offers new insights into surfactant-assisted crystallization for enhancing carbonated steel slag properties, paving the way for high-performance, eco-friendly building materials from industrial waste.

Enhancement of mechanical and tribological properties in glass fiber-reinforced polymer composites with multi-walled carbon nanotubes and ANN-based COF prediction

ABSTRACT The study investigated the effects of incorporating multi-walled carbon nanotubes (MWCNTs) into glass fiber-reinforced polymer composites on their mechanical and tribological properties. Experimental results demonstrated significant enhancements across various parameters. Microhardness increased by 25.03%, attributed to improved interfacial bonding and load transfer facilitated by MWCNTs. Tensile strength and modulus improved by 10.58% and 28.2%, respectively, indicating reinforced load-bearing capacity. Flexural strength and modulus increased by 33.78% and 36.29%, respectively, due to enhanced interfacial bonding. Inter-laminar shear strength (ILSS) exhibited a notable increase of 20.79% with MWCNT incorporation. Ity mpact toughness improved by 19.41% in Izod and 32.32% in Charpy tests, attributed to MWCNTs’ energy-dissipating properties and enhanced interfacial bonding. Tribological tests showed decreased wear and friction coefficients, along with reduced debris formation and fiber breakage in SEM analysis, indicating improved bonding between the matrix and fibers. Furthermore, an artificial neural network (ANN) model accurately predicted the coefficient of friction, aligning well with experimental values, offering potential for predictive modeling in composite material analysis. Overall, the incorporation of MWCNTs significantly enhanced mechanical properties and wear resistance of the composite material.

Density gradient structure foams prepared by novel two-step foaming strategy: Performance, simulation and optimization

Functional gradient foam materials play a crucial role in meeting the diverse performance and functionality requirements of modern engineering. Density gradients enable the distribution of mechanical, dielectric, and optical properties within materials, exhibiting a gradient representation. However, creating density gradients within foams poses a significant challenge, especially for semi-crystalline polymers. The paper proposed a novel two-step foaming method for preparing polypropylene (PP) foams with density gradient structure (DGS). Initially, a pre-foaming process was conducted to prepare PP pre-foams with uniform structure (US) at low temperatures, followed by a secondary foaming process on partially saturated PP pre-foams to fabricate PP DGS foams. By adjusting the duration of partial saturation time, PP foams with various DGS can be achieved. Compared with the commonly used one-step foaming method and uniform foaming method in the literature, the DGS foams prepared by the two-step foaming method exhibit not only a significant enhancement in mechanical property but also achieve the lowest thermal conductivity, while maintaining comparable and outstanding sound insulation performance. Finally, a comprehensive evaluation model using COMSOL Multiphysics was developed for the DGS foams, providing insights for optimizing foam performance through process enhancements.

Properties and mechanism analysis of a novel construction dust suppressant based on polymer blending

To address the poor suppression efficacy and limited mechanical properties enhancement of traditional dust suppressants in relation to construction dust, this study adopted polymer blending to prepare binding agent SA-PVA-CMC (SPC) utilizing sodium alginate (SA), polyvinyl alcohol (PVA), and carboxymethyl cellulose (CMC). Using a response surface methodology, the optimal mass concentrations of SPC, dodecyl dimethyl betaine (BS-12), and carboxymethyl chitosan (CMCS) were determined to be 0.317 %, 0.197 %, and 0.626 %, respectively, and a novel dust suppressant (SPC/CMCS/BS-12) was developed. The performance testing revealed the outstanding capabilities of the dust suppressant in binding, wetting, water retention, and moisture absorption. Dust treated with SPC/CMCS/BS-12 attained a compressive strength of 313.93 kPa, experiencing only a 2.73 % wind erosion rate under strong wind conditions (12 m/s). Furthermore, the dust suppressant achieved an 86.67 % efficiency in removing respirable dust and up to 93.21 % for total dust. The hydrogen bonding between polymer molecular chains and the adsorption between SPC/CMCS/BS-12 and the surface of construction dust enhance the mechanical properties of the construction dust.

Eco‐friendly enhancement of mechanical properties in 3D carbon felt reinforced epoxy/aluminum sandwich composites via NaCl‐based anodizing and triton X‐100 modification

AbstractTo address the challenges of achieving strong adhesion between aluminum face sheets and composite cores (3D carbon felts) in sandwich structures, this work presents a novel approach that prioritizes safety, environmental sustainability, and ease of processing. The 3D CFs/Epoxy core was modified with Triton X‐100 in amounts from 0 to 10 wt% of the epoxy resin. The aluminum alloy face sheets were anodized at voltages from 0 to 11 V, using a NaCl‐based anodizing process. The technique of anodizing can enhance the bond between the aluminum face sheets and the 3D CFs/epoxy core, resulting in improved mechanical performance of the composite, including flexural and compressive testing, as well as dynamic mechanical analysis. The composite, embedding 3D CFs foam in epoxy resin, has a storage modulus 65.1% higher than pure epoxy at 2070 MPa. In addition, increasing Triton X‐100 content (1–10 wt%) decreases the storage modulus from 1886 to 1314 MPa and the glass transition temperature from 68.3 to 62.8 °C. Additionally, with Triton X‐100 concentrations of 1 to 10 wt%, the flexural modulus of the epoxy reinforced by 3D CFs drops from 3951.8 to 2400 MPa, and the flexural strength decreases by 55.3% from 174 to 112 MPa, indicating reduced structural rigidity. For sandwich composites with anodized aluminum face sheets, a 7 V anodizing voltage boosts the flexural modulus from 17.8 GPa (0 V) to 36.2 GPa. At 7 V, compressive strength and strain rise by 346.9% and 995.5%, respectively. Flexural toughness peaks at 11239 KJ/m3 with 5 wt% Triton X‐100.Highlights Developed new sandwich epoxy composites consisting of anodized aluminum sheet treated with NaCl and modified 3D carbon felts epoxy composites using Triton X‐100. Aluminum face sheets underwent an anodization at different voltages (0, 5, 7, 9, and 11 volts), aiming to enhance the bonding between the aluminum sheets and the 3D CFs/epoxy core. Triton X‐100 was utilized to modify the epoxy matrix at various concentrations (0 to 10 wt%) for improving the flexibility of the sandwich core. The sandwich composites incorporating the un‐anodized face sheet have shown flexural modulus of about 17.8 GPa. The modulus achieves its maximum value of 36.2 GPa when anodized at 7 V, indicating a 103% increase. The flexural strength of sandwich composites increases by 13% (272 MPa) when the Triton X‐100 concentration is raised to 5 wt%, compared to the 240 MPa flexural strength of the Al face sheet anodized at 7 V.

Nanowires for Solid‐State Lithium Batteries

AbstractA vital approach to accessing high‐safety and high‐energy‐density lithium batteries is to develop solid‐state electrolytes (SSEs) instead of liquid electrolytes. However, lithium‐ion transport and interface stability issues puzzle the construction of solid‐state lithium batteries (SSLBs). Thus, developing fast‐ionic conductors with high electrochemical performances and chemical stability is crucial to SSLBs. Nanowires (NWs) possess high aspect ratios for maintaining carrier transport along the radial direction, thus being extensively employed in SSLBs for the enhancement of ion transport efficiency, mechanical properties, thermostability, flame retardancy, and interface stability between electrodes and electrolytes, consequently boosting the cycle stability and safety of SSLBs. In this work, the advances in NWs for SSLBs, from rational design and synthesis strategies to applications in composite cathodes, anode materials, and SSEs of SSLBs, are systematically reviewed. The key role of NWs in electrodes and the enhancement mechanism of SSE performance by introducing NWs are concluded in detail. Finally, the existing challenges and anticipated prospects for the future development of advanced nanowire‐based SSLBs are summarized and demonstrated. This review aims to provide a comprehensive understanding to facilitate the application of NWs in SSLBs.

A method of pretreating incineration ashes containing metallic aluminium using NaOH to mitigate volume expansion under highly alkaline conditions

Globally, millions of tonnes of incineration ashes are produced with a substantial portion remaining underutilized in low-value applications or disposed in landfills. Many types of fly ashes and bottom ashes contain metallic aluminium (Al0), which causes volume expansion when the ashes are used in alkali-activated materials and as a supplementary cementitious material due to the generation of hydrogen gas at high-pH conditions. This phenomenon significantly restricts the potential applications of these ashes. To address this issue, ashes can be pretreated with NaOH to oxidize the metallic aluminium (Al0) before their utilization. This study focuses on investigating the effect of the NaOH pre-treatment duration on fly ashes from the co-combustion of recovered solid fuel, peat, and wood. A pre-treatment process was conducted using 8 mol/L aqueous NaOH solution to treat the fly ash for up to 60 minutes. The formed slurry was subsequently used to prepare alkali-activated material by mixing it with bottom ash and employing either sodium silicate or sodium carbonate as an alkali activator. The NaOH pre-treatment demonstrated a 100 % metallic aluminium conversion into oxidized form resulting enhancement in mechanical performance, microstructure, and water absorption properties. The proposed method offers a highly efficient and rapid solution for eliminating the drawbacks caused by the presence of metallic aluminium and it can be conveniently implemented on construction sites. Concurrently, this study also explores the leaching behaviour of heavy metals during alkali-activation. Significant reductions in the leaching of Ba, Cr, Cu, Mo, and Pb were observed, highlighting the environmental remediation potential of alkali-activation methods.

Pinewood biochar antistatic polymer composites: an investigation of electrical, mechanical, rheological and thermal properties

ABSTRACT This study investigates the practical applications of biochar as an innovative and sustainable conductive filler in composite materials. Utilizing the conventional melt-blending method, we prepared conductive pinewood biochar-filled poly(lactic acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) composites and systematically examined their electrical, mechanical, rheological and thermal properties. Our results reveal a significant enhancement of electrical and mechanical properties upon the inclusion of conductive pinewood biochar in the PLA/PBAT matrix. With the addition of 10 wt% of conductive pinewood biochar, the average surface resistivity of the composites decreased by three orders of magnitude, measuring 4.86 × 10 10 Ω / sq , which meets the antistatic requirements for polymer composites. Additionally, the average tensile strength of the biochar filler composites improved by 53% with an addition of just 1 wt% of biochar.

Effect of cryogenic treatment time on mechanical properties of Sm2Co17 permanent magnets

Sm2Co17 permanent magnets are widely used in aerospace, radar communication, rail transit, and various other fields. However, their brittleness restricts their application. Improving their mechanical properties is of practical interest. Cryogenic treatment can be used as a means to enhance the mechanical properties of Sm2Co17 permanent magnets. However, the specific relationship between cryogenic treatment time and the properties of samarium-cobalt magnets has not yet been fully understood. In light of this, this paper focuses on exploring the influence of cryogenic treatment time on the mechanical properties of Sm2Co17 permanent magnets, aiming to provide a foundation for further elucidating this relationship. The results show that the mechanical properties can be significantly affected by cryogenic treatment time, with the flexural strength and elastic modulus increasing by 27.6 % and 9.6 % respectively when 3 h of treatment. However, the effect of further extending the treatment time to 6 h is not significant. In addition, the cryogenic treatment time has no adverse effect on magnetic properties. Additional analysis reveals that the enhancement in mechanical properties is primarily attributed to the decrease in residual stress and lattice constants. This study provides valuable insights into optimizing cryogenic treatment parameters to enhance the mechanical performance of Sm2Co17 permanent magnets while preserving their magnetic properties.

Effect of modified multi-walled carbon nanotubes on mechanical properties and microscopic mechanism of lithium slag geopolymers

This study aims to examine the impact of multi-walled carbon nanotubes (MWCNTs) on the mechanical properties and micro-mechanisms of lithium slag geopolymer (LSG), a novel environmentally friendly building material. Two distinct dispersion methods, which used ultrasonication or added sodium dodecyl sulfate (SDS) dispersants, were employed to disperse both pristine and modified MWCNTs. Subsequently, these dispersed MWCNT solutions were mixed with waste lithium slag and stirred to prepare LSG. Based on the experiments, it is concluded that all of these demonstrated the most significant enhancement of LSG mechanical properties at a 0.1 % mass fraction of modified MWCNTs. In comparison with the reference LSG, the compressive and bending strengths of LSG with modified MWCNTs experienced improvements of 23.29 % and 13.76 %, respectively, after a curing period of 28 days. This was also evident from a microscopic perspective. The LSGs doped with modified MWCNTs and SDS exhibited stronger Ai-O-Si and Si-O-Si vibrational bands, as well as broader N-A-S-H and C-S-H characteristic peaks compared to the pristine LSGs. The porosity of LSG samples mixed with a mass fraction of 0.1 % MWCNTs and SDS was 37.08 % lower than that of pristine LSG. FESEM electron micrographs revealed that the modified MWCNTs functioned as fillers, bridges, and extractors of cracks in the hydration products of LSG. The aforementioned results suggest that well-dispersed modified MWCNTs have a beneficial impact on the mechanical properties and microscopic characteristics of LSG.

Unexpected self-healing acceleration within urethane networks: lignosulfonate mediation of ionic and hydrogen bonds for ultra-strong recyclable elastomers

Stiff structures are generally considered detrimental to the materials’ self-healing efficiency because of the rigid conformation and restricted motion of the molecular chains. However, in this study, an unexpected acceleration in self-healing was observed in a urethane network when lignosulfonate, a bio-based stiff structure with stiff benzene rings, was introduced into the polyurethane matrix. An extraordinary increase in mechanical properties was achieved with just 3 wt% lignosulfonate added to the pristine sample, including a strength increase from 16.24 MPa to 42.89 MPa and elongation at break from 390% to 602%. Importantly, this significant enhancement in mechanical properties was accompanied by a notable acceleration in healing time efficiency, which increased by up to 44% compared to the pristine sample. This unique behavior can be attributed to the mediation of lignosulfonate on the ionic bonds between lignosulfonate and the urethane segment, as well as the hydrogen bonds formed within the urethane segments. This mediation ensures ultra-high strength without compromising the self-healing capacity and opens a way for accelerating elastomers self-healing efficiency through lignosulfonate, a readily available biomass-derived material. In addition, the addition of lignosulfonates gives the elastomer some Anti-UV performance.

Unveiling the mechanical and microstructural properties of SiC reinforced aluminum wires recycled from scraps by friction stir extrusion

Friction Stir Extrusion (FSE) has been proven as an effective solid-state process to directly recycle metal chips into high-quality wires/rods/tubes. However, the demand for Al-based composite wires with enhanced properties is substantial, and achieving a uniform distribution of the strengthening phase within the composite wire by establishing a robust metal/ceramic interface remains a significant challenge. In this study, AA6082 Aluminum alloy wires reinforced with 12.5 vol% SiC particles, exhibiting homogeneous particle distribution and superior mechanical properties, were successfully produced through the FSE technique. The investigation focused on examining the influence of processing parameters and the addition of SiC reinforcement on the microstructure and mechanical characteristics of the extruded wires. Scanning electron microscopy (SEM), Electron Backscatter Diffraction (EBSD), together with microhardness, bending, and tensile tests, were used to comprehensively analyze the resulting properties. The findings demonstrate a substantial enhancement in the wires' mechanical properties due to the SiC particles. Both tool rotation and tool force were varied during the experimental campaign. Notably, the reduction in porosity and grain refinement resulted in a 12.78 % increase in tensile strength and an 18.6 % improvement in microhardness compared to Al 6082 alloy extruded wires. Grain orientation analysis revealed a fully recrystallized microstructure with a weak texture. Furthermore, the study evaluated power consumption and surface roughness while assessing the feasibility of deposition, thereby highlighting the potential application of this technique in advanced additive manufacturing processes.

Enhancement of mechanical and ferromagnetic properties of Cd0.4Mn0.6XO nanocomposites (X=ZnO, SnO, CuO, Al2O3, Fe2O3, CoO, NiO)

Structural, mechanical and ferromagnetic characteristics of hydrothermally synthesized Cd0.4Mn0.6XO nanocomposites were investigated. The characterization of Cd0.4Mn0.6XO was accomplished using XRD, TEM, FTIR, photoluminescence and VSM techniques. The XRD showed the formation of monoclinic Cd2Mn3O8 alongside other phases. The crystallite size has no systematic trend against the valence state of ions. The particle size has minimum value (9.75 nm) for ZnO, and maximum values of 31.39 nm and 35.61 nm were observed for Al2O3 and Fe2O3, respectively. Similarly, typical enhancements are achieved for the mechanical and ferromagnetic parameters, e.g. they are increased when ZnO is replaced by Al2O3 and significantly enhanced by Fe2O3. In contrast, they were reduced by the other X, but they are still higher than ZnO. The photoluminescence of Cd0.4Mn0.6XO shows violet, blue, green, and orange emissions. The reported results indicate a strong correlation between the mechanical and ferromagnetic properties of nanocomposites against the particle/crystallite sizes and valence state.

Towards enhanced elevated-temperature mechanical properties by regulation of eutectic structure in Al-Cu-Si alloys solidified under super-gravity field

High volume fraction of tri-phase eutectic structure is challenging to obtain in ternary alloys through conventional methods. Currently, we reported that super-gravity solidification can be utilized to obtain high-volume fraction Al-Al2Cu-Si tri-phase eutectic structure in Al-Cu-Si alloys. The refinement of the eutectic structure can be detected mainly due to the enhancement of mass transfer, affecting the nucleation rate and growth of eutectic phase in the Al-Cu-Si eutectic system. Interestingly, the refined Al2Cu and Si eutectic structures are stable even up to 300 °C thermal exposure without obvious coarsening, contributing to the enhancement of elevated-temperature mechanical properties (∼268.8±8.8 MPa at 300 °C), which is ∼51.9 % higher than those solidified under normal gravity field (∼177.0±1.9 MPa). The refinement and homogeneous distribution of more Al-Al2Cu-Si tri-phase eutectic structures provide better stress dispersion, favoring crack initiation and propagation within the tri-phase eutectics, resulting in a transition from brittle fracture to ductile fracture mode.